SSM框架搭建简单实例

简介

Spring+SpringMVC+MyBatis框架（SSM）是比较热门的中小型企业级项目开发的框架，对于新手来说也是比较容易学习入门的。虽说容易，但在框架搭建过程中仍然遇到了许多问题，因此用实例记录下来吧。

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实例

第一步——导包

Spring框架包及其依赖包
MyBatis框架包及其依赖包
MyBatis-EhCache架包
C3P0架包
MySql数据库驱动包

项目架包如下：

项目结构如下：

第二步——整合Dao层（Spring+MyBatis）

sqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration>    <settings>        <setting name="cacheEnabled" value="true"/>    </settings></configuration>

因为MyBatis交给Spring管理，因此Mapper在Spring中配置，这里的配置只打开二级缓存

applicationContext-dao.xml

    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">        <property name="driverClass" value="com.mysql.jdbc.Driver" />        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/db_pwc" />        <property name="user" value="pwc" />        <property name="password" value="123456" />        <property name="maxPoolSize" value="20" />        <property name="minPoolSize" value="1" />        <property name="initialPoolSize" value="3" />        <property name="maxIdleTime" value="15" />    </bean>    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">        <property name="configLocation" value="classpath:sqlMapConfig.xml" />        <property name="dataSource" ref="dataSource" />    </bean>    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">        <property name="basePackage" value="cn.pwc.dao.mapper" />        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />    </bean></beans>

1.该配置自动扫描单例化采用代理方式的Mapper，单例化的Mapper的bean名为Mapper接口第一个字母为小写的名。
2.千万要注意sqlSessionFactory的bean中的configLocation属性，其value值务必记得加上classpath:前缀，不然无法加载MyBatis配置文件

第二步——整合Service层（Spring）

业务接口和业务实现

UserService.java

package cn.pwc.service;import java.util.List;import cn.pwc.pojo.User;public interface UserService {    public void add(User user) throws Exception;    public void delete(User user) throws Exception;    public User getUserById(int id) throws Exception;    public List<User> listUserByAge(int age) throws Exception;}

UserServiceBean.java

package cn.pwc.service.impl;import java.util.List;import javax.annotation.Resource;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import cn.pwc.dao.mapper.UserMapper;import cn.pwc.pojo.User;import cn.pwc.service.UserService;@Service @Transactionalpublic class UserServiceBean implements UserService{    @Resource(name="userMapper")    private UserMapper mapper;    @Override    public void add(User user) throws Exception {        mapper.insert(user);    }    @Override    public void delete(User user) throws Exception {        mapper.deleteById(user.getId());    }    @Override    public User getUserById(int id) throws Exception {        User user=null;        user=mapper.findById(id);        if(user==null){            throw new Exception("User is not existed!");        }        return user;    }    @Override    public List<User> listUserByAge(int age) throws Exception {        List<User> list=null;        list=mapper.findByAge(age);        if(list==null){            throw new Exception("List is empty!");        }        return list;    }}

本实例采用自动扫描加载的方式，因此该业务bean需注解@Service
本实例交由Spring管理事务，因此该业务bean需注解@Transactional

applicationContext-service.xml

    <context:component-scan base-package="cn.pwc.service" />

第三步——添加事务管理

applicationContext-transaction.xml

    <bean id="txManager"        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">        <property name="dataSource" ref="dataSource" />    </bean>    <tx:annotation-driven transaction-manager="txManager" />

第四步——整合视图层（SpringMVC）

springmvc.xml

    <context:component-scan base-package="cn.pwc.controller"/>    <mvc:annotation-driven />    <bean        class="org.springframework.web.servlet.view.InternalResourceViewResolver">        <property name="prefix" value="/" />        <property name="suffix" value=".jsp" />    </bean>

采用mvc:annotation-driven标签自动装载视图控制器处理器解析器等

视图Controller（HelloController.java）

package cn.pwc.controller;import javax.annotation.Resource;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;import cn.pwc.pojo.User;import cn.pwc.service.UserService;@Controllerpublic class HelloController {    @Resource(name="userServiceBean")    private UserService service;    @RequestMapping("/hello")    public ModelAndView sayHello(){        User user=null;        User user2=null;        User user3=null;        try {            user = service.getUserById(1);            user2=service.getUserById(1);            user3=service.getUserById(1);            System.out.println("OK!");        } catch (Exception e) {            e.printStackTrace();        }        ModelAndView view=new ModelAndView("hello");        view.addObject("user", user);        return view;    }}

该Controller类需注解@Controller
视图控制方法需注解@RequestMapping，作为url请求处理方法

第五步——将所有配置装载到Spring容器中

web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns="http://java.sun.com/xml/ns/javaee"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"    id="WebApp_ID" version="3.0">    <listener>        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>    </listener>    <context-param>        <param-name>contextConfigLocation</param-name>        <param-value>classpath:applicationContext-*.xml</param-value>    </context-param>    <servlet>        <servlet-name>springMVC</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:springmvc.xml</param-value>        </init-param>    </servlet>    <servlet-mapping>        <servlet-name>springMVC</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping></web-app>

务必注意servlet-mapping中url-pattern属性值不能为/*
加载的配置文件路径必须有classpath:前缀

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测试